Clamping Retractor Assembly

ABSTRACT

An assembly for retracting soft tissue in a surgical incision, the assembly comprising; a supporting member having first and second ends; a refractor blade having a first distal end and a second proximal end retained at the first end of the support member; a retaining arm which co operates with the support member and receives and supports a clamping assembly; an adjusting assembly which engages the support member and allows the clamping assembly to advance and retract relative to the retractor blade.

BACKGROUND

The present invention relates to retraction assemblies and moreparticularly relates to assemblies for retracting soft tissue duringsurgery and particularly during spinal surgery. The invention furtherrelates to a G clamp retractor which has an internal component whichengages a wound to retract soft tissue and an external component whichhas the capacity to set and control the degree of retraction. Theinvention further relates to an assembly which more efficiently retractsthe psoas muscle to allow access to spinal vertebrae.

PRIOR ART

In the field of surgery, conventional retractors used in applicationssuch as spinal surgery include a retractor blade portion that is incontact with the soft tissues and a handle portion that controls theblade position. The blades are inserted into position through thesurgical wound. The direction of force applied by the blades to keep thewound open is usually at right angles to this line of entry. Thiscreates mechanical disadvantage and complex mechanisms may need to beemployed to overcome tissue resistance—i.e. the tendency or bias of awound towards closure. As most retractors operate from the woundsurface, the distance from the wound surface to the point of contactbetween retractor blades and the tissue works similar to a verticalcantilever which is suboptimal for the surgeon's requirement for accessto the site and also a free end cantilever is not ideal as there issignificant force applied at the free end of the retractor by softtissue. A short retractor handle is generally easier to control andapply force with as the moment is lower. In a long blade the moment ishigher. This is especially true when handle is roughly parallel withblade. Strong mechanisms are sometimes required, strong materialsneeded. Also the known mechanisms occupy space restricting the surgeonsaccess and they may also be complex. The stability of the retractor mayalso be a problem. Some dual or multi bladed retractors apply spreadingforces against the wound edges to stabilize retractors but these applyforce that may potentially injure tissues unnecessary for the purpose ofexposure but in order to gain retractor stability. Stability isdesirable but tissue injury is not. An alternative solution is to usetable mounted mechanisms with long mechanical arms but these have greatmechanical inefficiency because of the distance from point of fixationi.e. the table, to the point of at which retraction pressure is applieddistally. This problem of the difficulty in applying force and retractorinstability is worse the deeper the wound and especially when deepstructures require refraction.

Spinal operations for various conditions commonly require deep woundsespecially when the approach is lateral, anterior lateral or anterior tothe spine. Retracting the psoas muscle posteriorly to expose the lateralor anteriolateral spine can be problematic because of the size of themuscle and the depth of the wound. At L45 from a lateral approach thisis made even harder because the iliac crest commonly impedes truelateral access for the retractors and instruments, meaning an obliqueapproach to the spinal disc may be required.

In many spinal operations the retractors lack stability e.g. with deepmulti bladed retractors and various forms of tubular refractors. Suchretractors regularly require table fixed adjustable arms to improve thestability for the retractor.

Conventional retractors work directly through the surgical wound.Retractors are known that are employed in endoscopic surgery which enterthe abdominal cavity via separate ports or incisions. These workdirectly and do not connect with other parts of a retractor system.There is a system described in the paper by Rao modified from Nakamura.(J Neurosurg Spine 5:468-470, 2006 entitled “Dynamic retraction of thepsoas muscle to expose the lumbar spine using the retroperitonealapproach”

-   Technical note:-   GANESH RAO, M.D., ROBERT BOHINSKI, M.D., PH.D., IMAN FEIZ-ERFAN,    M.D., AND LAURENCE D. RHINES, M.D.-   Nakamura H, Ishikawa T, Konishi S, Seki M, Yamano Y: Psoas-   strapping technique: a new technique for laparoscopic anterior    lumbar interbody fusion. J Am Coll Surg 191:686-688, 2000)

That paper describes a technique which applies retraction force via athread through the patient body wall. A conventional approach is usedfor the main operation. Tissues are retracted by passing thread throughthe psoas muscle on a needle. The needle is then removed from thread. Ahollow needle is passed through the body wall. Both ends of the threadare then passed through the hollow needle outside the skin. Threads arepulled to gain psoas retraction and then anchored with a forceps whichis pulled back by the muscle force against the skin. This systemprovides for efficient application of retraction force by line of pullbeing as close as possible to the desired direction of retraction and byavoiding a cantilevered handle.

It would be advantageous if retraction was applied to the psoas muscleby a blade rather than by a thread as blades retract muscle smoothly andare less injurious to surface nerves than the potential strangulationeffect from a thread. Blades can also be selected to fit the anatomyunder retraction. The blind needle passage may also damage nerves withinthe psoas muscle. Threading a needle in a wound is fiddly, threadspassing through retractor tissues have less stability than a handle.Threads passed through a muscle cannot be repositioned easily.

It would be an advantage in such operations to have a method ofretracting the psoas muscle posteriorly to expose the spine or the discspace that avoids the force application and distribution problemsassociated with deep wounds, long handles and oblique access. Theseknown surgical retraction methods currently all lead to retractorsworking at considerable mechanical disadvantage.

It would be an advantage to reduce or eliminate the mechanicaldisadvantage occasioned by the known retraction devices and assembliesand to improve retractor stability and to avoid the aforesaid problems.

The present applicant has previously described devices to improvemechanical advantage for retraction using bone fixation combined withmechanisms to allow retractor blade rotation.

INVENTION

The present invention provides an assembly which more efficientlyretracts muscle to allow access to spinal vertebrae. The presentinvention further provides an assembly which more efficiently retractsthe psoas muscle to allow access to spinal vertebrae. The presentinvention also provides a method of retraction of soft tissues duringspinal surgery which ameliorates the problems of the prior artassemblies and methods.

According to one embodiment a retractor blade and handle are insertedthrough a main wound. A second handle is inserted through a separateincision. Blade and second handle are then connected in the main wound.Pulling the second handle retracts the blade and tissues efficiently ina preferred direction. The assembly described herein allows themaintenance of the required amount of refraction and maintenance of theretractor position and without either manual holding or securing of theretractor handle to a table mounted arm. Passage of the second handlethrough the body wall limits motion except for motion in line with thehandle. Limiting the motion of the refractor handle further is achievedby its relationship with a plate. The plate is in contact with the bodywall. Internally the muscle under retraction exerts a pull on therefractor and its handle. Internal movement of the handle is howeverprevented by an adjustable stop on the handle which is forced againstthe plate by the retractor pull. Retraction can be adjusted by movementof the stop.

In its broadest form the present invention comprises:

-   an assembly for retracting soft tissue in a surgical wound, the    assembly comprising;-   a retractor blade having a first distal end and a second end which    includes an associated support member,-   a retaining member having a distal end which engages the support    member and a second proximal end which includes a hand operable    clamping assembly;-   an adjustable stop which engages a plate, wherein the plate engages    a skin surface of a patient to resist said retraction by the soft    tissue as the support member is urged to induce retraction by the    blade.

According to a preferred embodiment, the support member includes aformation which co operates with a guide member. Preferably theformation is an opening which receives an end of the guide member.According to one embodiment the retaining arm includes at least onethreaded region which co operates with said plate, adjustable stop and alocking nut. The guide member co operates with the support member toenable setting of a retraction condition. The assembly allows adjustmentof retraction by increasing or decreasing a retraction force.

In another broad form the present invention comprises:

-   an assembly for retracting soft tissue in a surgical wound, the    assembly comprising;-   a retractor blade having a first distal end and a second end which    engages an associated detachable first handle,-   a second handle having a first distal end which engages said blade    and a second proximal end which includes a hand operable control    element and intermediate therebetween an adjustable stop which    engages a plate,-   a guide which engages a second end of the first handle to facilitate    alignment of the second handle with an opening in the refractor    blade;-   wherein the plate engages a skin surface of a patient to resist said    retraction by the soft tissue as second handle urges said blade to    induce retraction.

According to a preferred embodiment the guide includes a first end whichco operates with the first end of the first handle and a second endwhich receives a distal end of the second handle thereby guiding thesecond handle into engagement with said retractor blade.

In another broad form of a method aspect the present inventioncomprises:

-   a method for retracting soft tissue in a surgical would during    spinal surgery using an assembly comprising;-   a retractor blade having a first distal end and a second end which    engages a support member;-   and an adjustable stop which engages a pressure plate which co    operates with the retractor blade during refraction by applying    pressure to the body of a patient,-   the method comprising the steps of;-   taking the retractor blade and attaching it to the support member;-   inserting the retractor blade into a surgical incision;-   adjusting a clamping assembly which co operates with a retaining    member to exert a retraction force on the retractor blade;-   allowing a bearing member to engage a skin surface of a patient;-   manipulating the support member to induce retraction of the soft    tissue against a bearing force applied by the bearing member    opposite to the direction of retraction.

The method according to one embodiment comprises the further step ofinserting the retaining member into a sleeve in the support member priorto engagement with the retractor blade and prior to insertion of theretractor into the incision.

In another broad form the present invention comprises:

-   an assembly for retracting soft tissue in a surgical wound, the    assembly comprising;-   a refractor blade having a first distal end comprising a blade arm    and a proximal end;-   a retaining arm and a clamping assembly which engages the retaining    arm having a first end which is slidably retained by said retention    arm and a second end which receives and retains a pressure plate    assembly; the clamping assembly including means to enable vertical    adjustment to alter the vertical position of the plate assembly    relative to the retaining arm.

In another broad form the present invention comprises:

-   an assembly for retracting soft tissue in a surgical wound, the    assembly comprising;-   a retractor blade having a first distal end comprising a blade arm    and a proximal end comprising a retaining arm; a clamping assembly    which engages the retaining arm having a first end which is slidably    retained by said retention arm and a second end which receives and    retains a pressure plate assembly; the clamping assembly including    means to enable fine clamping adjustment of the pressure plate when    the clamping assembly is set in a selected location along the    retaining arm; the fine adjustment determining the extent of    clamping force exerted between the blade arm and the pressure plate.

According to a preferred embodiment, the clamping assembly is adjustablerelative to the retention arm thereby enabling locking adjustmentbetween the clamping assembly and the blade arm. Preferably, theclamping assembly is telescopically adjustable and includes openingswhich receive a locking pin which enable the clamping assembly to adoptvarious vertical positions. The plate assembly allows fine horizontaladjustment according to the clamping force required. The plate of saidplate assembly engages a skin surface of a patient to provide anopposing force against retraction of soft tissue to maintain the desiredrefraction force.

In another broad form the present invention comprises:

-   an assembly for retracting soft tissue in a surgical wound, the    assembly comprising;-   a retractor blade having a first distal end comprising a blade arm    and a proximal end comprising a retaining arm; a clamping assembly    which engages the retaining arm having a first end which is slidably    retained by said retention arm and a second end which receives and    retains a pressure plate assembly; the clamping assembly including    means to enable horizontal adjustment to selectively alter the    distance between the blade arm and the clamping assembly.

The present invention provides an alternative to the known prior art andthe shortcomings identified. The foregoing and other objects andadvantages will appear from the description to follow. In thedescription reference is made to the accompanying representations, whichforms a part hereof, and in which is shown by way of illustrationspecific embodiments in which the invention may be practiced. Theseembodiments will be described in sufficient detail to enable thoseskilled in the art to practice the invention, and it is to be understoodthat other embodiments may be utilized and that structural changes maybe made without departing from the scope of the invention. In theaccompanying illustrations, like reference characters designate the sameor similar parts throughout the several views. The following detaileddescription is, therefore, not to be taken in a limiting sense, and thescope of the present invention is best defined by the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a perspective view of a retraction assembly according toone embodiment.

FIG. 2 shows with corresponding numbering a perspective view of theassembly of FIG. 1 including a guide member with trochar.

FIG. 3 shows an enlarged view of a guide assembly.

FIG. 4 shows an enlarged view of the plate and sleeve of FIG. 2.

FIG. 5 shows the handle in isolation from the assembly of FIG. 2.

FIG. 6 shows an elevation view of a retraction assembly according to analternative embodiment;

FIG. 7 shows an end view of the retractor blade of FIG. 6;

FIG. 8 shows a top view of the retractor blade of FIG. 6;

FIG. 9 shows an opposite end view of the retractor blade of FIG. 6.

FIG. 10 shows a side elevation view of a retractor assembly according toan alternative embodiment.

FIG. 11 shows with corresponding numbering a cross sectional elevationview of the retractor assembly of FIG. 10.

FIG. 12 shows a top view of the connector engaging support member.

FIG. 13 shows the clamping member separated from retaining arm androtated 90 degrees.

FIGS. 14 a-e show various configurations of retractor blades.

FIG. 15 shows a schematic arrangement of a retractor assembly in use.

FIG. 16 shows a cross sectional elevation of a clamping retractorassembly showing a tooth of a retractor blade engaging an annulus.

FIG. 17 shows a surgical incision in the skin of a patient withretractor blade in use.

FIG. 18 shows a surgical incision in the skin of a patient with a GClamp according to the invention and used in conjunction with anotherretractor and offset tool.

FIG. 19 shows a cross sectional elevation of the arrangement of FIG. 18showing a reverse tooth of a retractor blade engaging an annulus.

DETAILED DESCRIPTION

The examples referred to herein are illustrative and are not to beregarded as limiting the scope of the invention. While variousembodiments of the invention have been described herein, it will beappreciated that these are capable of modification, and therefore thedisclosures herein are not to be construed as limiting of the precisedetails set forth, but to avail such changes and alterations as fallwithin the purview of the description.

FIG. 1 shows a perspective view of a retraction assembly 1 according toone embodiment. Assembly 1 for refracting soft tissue in a surgicalwound comprises a retractor blade 2 having a first distal end 3 and asecond end 4 which includes an associated handle 5. Assembly 1 furthercomprises a one piece trochar handle 6 having a pointed tip first end 7which engages blade 2 and a second end 8 which includes a manualoperating control element 9. Intermediate therebetween is adjustablestop 10 which engages a plate 11, wherein the plate engages a skinsurface of a patient to resist retraction by the soft tissue. Trochar 6also includes a locking nut 12 which co operates with thread 16 andenables locking of the plate 11 in a particular position for apredetermined extent of retraction. A washer which is not threaded canbe employed as an alternative to plate 11. Retractor blade 2 has at itsproximal end 4 a female recess 17 which receives male profile parts 18which prevent rotation of blade 2. External refractor handle 5 hasthreaded bolt 25 that secures handle 5 to top surface recess 17 of blade2. Square recess 27 to receives guide 13. Handle guide assembly 13receives via end 36 sleeve 19, trocar or handle 6.

FIG. 2 shows with corresponding numbering a perspective view of theassembly of FIG. 1 Handle 5 includes a formation 27 which co operateswith a guide member 13 (see FIG. 1). The formation 27 is an openingwhich receives an end of the guide member 13. According to oneembodiment the second handle trochar 6 in FIG. 1 is replaced by analternative handle H which includes at least one threaded region 34which co operates with plate 11, adjustable stop and a locking nut 12.The guide member 13 co operates with the first handle 5 to enablesetting of a refraction state. The assembly 1 allows adjustment ofretraction by increasing or decreasing a retraction force. Plate 11 ispreferably threaded for sleeve 19.

Typically a surgical wound is opened to expose or partially expose thesurgical target. Structures and soft tissues to be retracted areidentified. Refractor blade 2 of assembly 1 as shown in FIG. 1 isattached to a handle 5 and is inserted through an open wound andpositioned. Threaded trocar 6 is passed through the wall of a patient'sbody through a separate wound along a line of a preferred line ofretraction force to be established. The trocar 6 is then screwed intoretractor blade 2 with end 7 penetrating opening 15. Pulling this trocar6 applies the correct line of retraction force and thus acts as a secondhandle. Although a retraction force may be applied continuously bypulling with the hand, the retractor 5 can be stabilized at a desiredposition by turning nut 12 with washer on proximal part of trocar 6until stop plate 11 contacts skin. Washer and nut 12 resists tissue pullon the handle by pressure on the external body wall. Handle 1 may beremoved from blade 5 or left attached to help further adjustment.Turning nut 12 can adjust retractor blade 5.

A more complex arrangement is also envisaged, and described below usingseparate trocar 6 with sheath, and guide system 13. As can be seen inFIG. 1 trochar locates in sheath 19. This employs some of the followingadditional elements:

-   -   1. Method and apparatus for precise positioning of the trocar 6        so that it aligns with ideal blade position. I.e. Guide.    -   2. Large plate 11 and nut 12 are replaced with other mechanisms        that spread muscle force over body wall. Such mechanism includes        a separate plate that a sleeve engages via threads as shown in        FIG. 1. Both envisaged embodiments of plate and washer variants        increase surface area and are shaped to reduce chances of skin        injury.    -   3. Sleeves which pass through body wall may also be employed        with trocar 6.

Purpose of the sleeve

-   -   a. By having increased width of sleeve over trocar 6, this        increases resistance to motion in line of body wall and thus        provides a more stable position for the handle.    -   b. Such a sleeve 19 may also be attached to plate 11 thereby        making plate 11 more stable.    -   c. By fixation to plate 11, sleeve 19 transmits forces from        handle 6 to plate by presence of large collar 10 which engages        nut 12 on handle 6.    -   d. Such a sleeve 19 allows trocar 6 to be removed and replaced        with a threaded handle. This avoids having unguarded threads        passing through body wall.    -   e. Length of sleeve and trocar can be made so that adjusting nut        12 on trocar 6 or handle limits depth that trocar or handle can        penetrate.    -   f. Sleeve 19 may be adjustable relative to plate 11 which        controls depth of sleeve 19 within the body.

FIG. 3 shows an enlarged view of a guide assembly 20 isolated from theretraction assembly with trochar 22 engaged with end 36. Assembly actsas a positioning guide and comprises an adjustable frame 21 which actsexternally as a guide and a safety stop for trocar 22 and sleeve (seeFIG. 4). Guide assembly allows correct positioning internally ofpercutaneous handle 22 by indicating a finishing position andattitude/direction. Guide 20 is adjustable, with indicator 23 toindicate distance from external guide to a safety stop which can be usedto set correct length of trocar and sleeve. External guide assembly 20can be opened to allow removal of guide 20 once trocar 22 and sleeve(not shown) is positioned. FIG. 3 shows frame 20 engages with adjustablemember 37. Member 37 engages frame member 21 via sleeve 38 which allowsmember 21 to slide relative to member 37. This allows the setting of apredetermined distance between the member 21 and member 37 so thesurgeon is able to determine the distance of penetration of handle 22into a second surgical wound to engage retractor blade 2 (see FIGS. 1and 2).

FIG. 4 shows an enlarged exploded view of the plate 11 and sleeve 19 ofFIG. 1. Plate 11 acts as an external Counter force plate and it will beappreciated that although the shape appearing in FIGS. 1 and 2 isannular other suitable shapes can be employed. Also a space frame orother contoured shape can be used as long as load is distributed evenlyagainst the patient body wall without injuring skin and to providemaximum stability. A disc could be used with a threaded opening forsleeve 19 and may include an additional washer. Sleeve 19 is preferablya threaded tube that screws through plate 11 to desired depth asreferenced from guide 20(see FIGS. 3). Sleeve 19 fits very tightlyaround trocar 6 of FIG. 1. Sleeve 19 has a large proximal collar 30 toacts as depth stop for handle 6. Sleeve 19 is connected to plate 11 andthen inserted through body wall with trocar 6 until plate 11 engages thebody wall. Sleeve 19 portion locates inside muscle and fat provide somestability. Amount of Sleeve protruding from plate 11 is set to haveminimal overlap over psoas muscle to avoid restricting movement of thepercutaneous handle.

FIG. 5 shows the trochar handle 6 in isolation from the assembly ofFIG. 1. Trocar 6 has a sharp pointed end 7 sharp pointed passes throughsleeve 19 (see FIG. 1) so that sleeve 19 is replaced with percutaneoushandle 6. Handle 6 includes a proximal thread 31 for adjustable nut 14or made so only slightly longer than sleeve 19 to prevent overpenetration and distal end thread 32 to engage blade 2 via opening 15.Handle 6 is inserted through body wall of a patient and guided bypositioning guide 20 with sleeve 19 around it. Sleeve 19 is attached tocounterforce plate 11. The percutaneous handle 6 slides in sleeve 19 andhas a proximal knob 33 to enable pulling and to prevent rotation whennut 12 is turned. This handle 6 is threaded distally (32) to engageblade 2 and threaded proximally (31) for large adjusting nut 12 toengage against collar 30 of sleeve 19. As handle 6 is pulled muscleinternally is retracted, large nut is spun on handle until it engagesplate which thus by counterforce on body wall secures handle inposition. More or less retraction is created by turning or releasing nut12. Once percutaneous handle 6 is attached to threaded opening 15 ofblade 2, initial open handle 5 can be retained to provide better andmore controlled guidance but once correctly positioned and secured bytension against counter plate, open handle 5 may be removed. Handle 5may be reattached as required.

The following describes how the assembly is used while adopting theguide 13. After wound opening, a guide 13 is positioned both internaland external to the wound. The external guide 13 sits against the skinaligning with internal guide 20 (see FIG. 2) which is positionedinternally at desired position of the end of the sleeve 19. Thisposition should also match with desired position for the perc handle.Measurements are read from guide 13 and using this as reference, sleeve19 is now rotated in threaded opening 21 portion of plate 11 so thatsleeve moves in or out relative to plate 11. Trocar 6 is inserted intosleeve 19 (with attached plate 11) and trocar 6 and sleeve 19 are theninserted through opening 22 of external guide 13, through the skintowards target. Once plate 11 is close to guide member 20, trocar 6 andsleeve 19 should be well engaged in tissues and preferably visibleinternally. External guide 13 is now opened to permit removal of guidefrom around sleeve 19. Sleeve 19 and trocar 6 are then advanced furtheruntil plate 11 engages skin and trocar 6 and needle are visibleinternally. The trocar 6 is withdrawn and a threaded handle with itsproximal nut is passed through the sleeve 19 and attached to retractorblade 5. Pulling this handle pulls retractor blade 2 in the correct lineof retraction force. This is handle number two. Although a retractionforce may be continued using hand pressure the retractor 5 can bestabilized by attaching to plate 11 pressing over a large area ofposterior body wall. Handle 1 may then be removed or left as desired.

Alternative Embodiments.

-   -   1. Instead of separate trocar and percutaneous handle 6, these        pieces could be Integrated into a 1 piece Trocar/handle which is        threaded distally to engage with internal blade 2 and proximally        for its own nut 12 to engage large washer. This embodiment        avoids the use of a sleeve 19. A washer may have slot, so that        drops over handle 6 after skin insertion, the nut on handle        engaging the washer directly    -   2. Instead of threaded nut, rack and pinion or other mechanisms        may be used to apply controlled forces between percutaneous        handle and sleeve collar.    -   3. Trocar or percutaneous handle instead of engaging blade may        also engage with handle 5.    -   4. Various mechanism e.g. key mechanism, split pins, various        axle fittings etc may be used to connect percutaneous handles        and blade. The Method of engagement may be varied to suit        requirements of handle e.g. if handle is needed to steer blade        other than simply by pulling, a larger handle maybe inserted        through a larger wound via a series of concentric tubes dilating        a channel through which handle is passed.    -   5. Blades can be any shape or size to suit local anatomy or        amount of retraction required.    -   6. Blades of different shape are interchangeable    -   7. Blades have cone shaped opening to allow easy positioning and        engagement of threaded part of handle.    -   8. Sleeve and plate could be one piece with set depth for sleeve    -   9. It is also envisaged that a targeting guide can be employed        instead of having an external guide that opens and closes around        handle as shown. External arm is reversibly fixed to plate.        Sleeve is separate from plate. Thus a hole in the plate        determines a correct alignment. Measurements are taken from a        frame about sleeve depth. Frame is unlocked. Sleeve is screwed        to correct depth which will push the plate away from the body        wall. Trocar and sleeve are inserted through body wall until        plate is flush with skin. Targeting guide is then removed.        Various variations of elements are possible all with same broad        intent and principles of action.    -   10. Guide function may be accomplished by incorporation of        sleeve and plate as part of external guide    -   11. Varying the angle of percutaneous handle thru body wall may        also impart downward or upwards force on retractor blade when        pulled which helps direct force of blade as desired.    -   12. It is also envisaged that a percutaneous handle could be        used to support an internal frame or mechanism that in turn        supports multiple retractor blades for e.g. a transpsoas        approach.    -   13. Internal frames supporting several blades may also be        supported by percutaneous handle e.g. peritoneal blade clip on        like an odontoid frame. A frame incorporating round bars in        order that blades might rotate is envisaged. Blades might be        fixed or hinge about sides of such frames.    -   14. Internal part of the guide may incorporate handle 1 as shown        in FIG. 5    -   15. A series of dilators may be passed over trocar 6 to create        protected passage for insertion of various handles that include        hooks or keying mechanisms for non threaded engagement with        blades.    -   16. Methododology. It is envisaged that handle is passed not        only from outside through skin and into wound but also from        wound out of skin, in which case handles and blades and other        parts are attached after tunneling.    -   17. Handles may be straight or curved with bosses and variations        of width with tapers to accommodate external threads and other        mechanisms to engage blades and other parts.    -   18. Retractor blades individual may be round or tubular in        various shapes.    -   19. Retractor blades may be individual or as part of Multibladed        retractors inserted individually or as part of assembly that        allows movements of blades. In this embodiment percutaneous        handle or handles attaches to some part of assembly adding to        stability or ability to control.    -   20. Multiple percutaneous handles may be employed.    -   21. Percutaneous handle may be similar to threaded Steinman pin,        inserted with power or hand driver. After insertion, insertion        handle or driver may be removed and detachable handle added with        nuts and washers for manual control and final positioning

Alternative Embodiment

FIG. 6 shows an elevation view of a retraction assembly 50 according toan alternative embodiment. Assembly 50 according to the embodiment shownis used for retracting soft tissue in a surgical wound and comprises aretractor blade 51 having a distal end 52 and a proximal end 53. Distalend 52 includes a formation 54 which locates inside a patient wound.FIG. 7 shows with corresponding numbering an end view of the retractorblade 51 of FIG. 6. Retractor blade 51 has a blade arm 55 whichterminates in distal end 52. Retaining arm 56 terminates in proximal end53 and includes openings 57 which allow incremental adjustment andbraking of clamp assembly 58 and finger opening 59 which allows anoperator to pull back on retaining arm 56 to urge blade arm 55 in thedirection of pull. This also allows movement of blade 51 relative toclamp assembly 58. This assists in setting different retraction statesand forces applied to soft tissue depending upon the surgical patientrequirements.

FIG. 8 shows a top view of the retractor blade of FIG. 6. Although blade51 is shown with blade arm 55 disposed normally to retaining arm 56,that angle can be varied according to design requirements and particularapplications and orientations of blade arm 55 required. Clamp assembly58 is shown engaged to retaining arm 56 via depending arm 60. Clampassembly further comprises adjustable support arm 61. Support arm 61 hasa recess 62 which receives and retains arm 60. Wheel 62 allowsadjustment of support arm 61 relative to depending arm 60. Recess 62allows travel of arm 61 relative to depending arm 60 thereby enablingthe adjustment of the distance indicated by H between retaining arm 56and shaft 63 of adjustment handle assembly 64. Arm 60 includes openings65 which allow selective adjustment of locking pin 66 so that height Hcan be adjusted by moving support arm 61 up or down. Support arm 61 hasat its distal end 67 an opening 68 which receives and retains shaft 63.End 69 of shaft 63 engages pressure plate 70 which includes outersurface 71 which in use engages the skin of a patient. End 69 as shownis contoured to enable relative movement between plate 70 and shaft 63.This allows the attitude of surface 71 of plate 70 to adjust to contoursof a patient. Plate 70 can rotate about an axis through shaft 63 and canalso tilt relative to that axis.

FIG. 9 shows an opposite end view of the refractor blade retaining arm56 as it engages depending arm 60. Arm 60 includes recess 72 whichreceives therein retaining arm 56. In use depending arm 60 is capable ofmovement relative to retaining arm 56 thereby enabling adjustment of thedistance between blade arm 55 and surface 71 of plate 70. Distance Ibetween blade arm 55 and surface 71 of plate 70 is adjustable dependingupon the patient. Adjustment handle 64 urges shaft 63 and plate 70 inthe direction of the patient or away from the patient. The plate 70engages a skin surface of a patient to resist retraction forces appliedto the soft tissue. Shaft 63 is according to one embodiment adapted witha threaded connection which engages distal end of the support arm 61.Turning handle 73 increases or decreases as required the gripping forcebetween surface 71 when in engagement with skin of a patient and theblade arm 55. Since depending arm 60 can be moved and repositioned alongretaining arm 56, this in addition to the adjustments enabled byadjustment handle assembly 64 accommodates different distances betweenthe blade arm 55 and plate 70. Also since clamp assembly 58 allowsadjustment of distance H the assembly 50 has wide scope of both verticaland horizontal adjustment to accommodate patient differences. Typicallya surgical wound is opened to expose or partially expose the surgicalfield. Structures and soft tissues to be refracted are identified.Retractor blade arm 55 of assembly 50 as shown in FIG. 6 is insertedthrough an open wound and positioned. Either before or after this clampassembly 58 is attached and adjusted vertically and horizontally asindicated above. Pulling on opening 59 initially manually applies therequired retraction force which is then locked into position andstabilised by urging plate 70 into engagement with the patient's skin.

FIG. 10 shows a side elevation view of a retractor assembly 80 accordingto an alternative embodiment. Assembly 80 comprises a first supportingmember 81 having a first end 82 and second end 83. First end 82 engagesan adjusting assembly 84 which comprises a connecting assembly 85.Second end 83 engages a connector 86 which retains a retractor blade 87.Depending from connecting assembly 85 is retaining arm 88 which retainsa height adjustable clamping member 89. Clamping member 89 is capable ofmovement relative to retaining arm 88 and comprises a first end 90terminating in a bearing face 91 which opposes retractor blade 87 and asecond end 92 which includes an actuating member 93 which enablesselective adjustment of the position of clamping member 89 relative toretaining arm 87. Connecting assembly 85 includes a runner 94 whichtravels along support member 81. Retaining arm 88 engages runner 94 viaend 95. Runner 94 further comprises an actuator 96 which engages supportmember 81 and contributes to retention of runner 94 in a positionselected by a user of the retractor assembly 80. Actuator 96 ispivotally attached to runner 94 by abutments 97 and 98. Locking knob 99retains runner 94 against first support member 81 and allows adjustmentof the runner 94 relative to supporting member 81. This allows a user toselectively adjust a distance between bearing face 91 and retractorblade 87. Support member 81 further comprises an array of teeth 100which allows incremental adjustment of connection assembly 85 alongsupport member 81. Actuator 96 engages corrugations or teeth on asurface of support member 81. In this case, teeth array 100 is shown onthe top of member 81. Actuator 96 can be arranged to engage teeth on oneor more surfaces. Formations 116 are able to be engaged by actuator 96to effect incremental adjustment of runner 94. Alternative formationscan be used to effect the incremental adjustment.

FIG. 11 shows with corresponding numbering a cross sectional elevationview of the retractor assembly 80 of FIG. 10. Retractor blade 87 engagesconnector 86 via end 101. Retractor blade 87 is fed into a slot 102located in connector 86. Clamping member 89 is selectively retainedalong retention arm 88 via a series of recesses 117 via locking rod 105.Locking rod 105 including leading end 106 which engages recess 104 toselect the position of clamping member 89. Actuating member 93 allowslocking rod 105 to be selectively withdrawn from recess 104 andrepositioned as required. Rod 105 is biased to a locking position viaspring 107 which urges rod 105 into engagement with recess 104. Torelease and move clamping member 89 requires the user to pull actuatingmember 93 against biasing spring 107. Retaining arm 88 is retained atend 109 at end 95 of by clamping assembly 85 via locking screw 110.Release of locking screw 110 allows arm 88 to be released from runner 94connection assembly 85.

FIG. 12 shows a top view of the connector 86 engaging support member 81.Connector 86 retains retractor blade 87 (see FIG. 10) via slot 102 whichand retains support member 81 via locking pin 103 which engages end 83.Teeth array 100 can be seen on the top surface of support member 81.

FIG. 13 shows the clamping member 89 separated from retaining arm 88 androtated 90 degrees. From this view opening 111 which retains arm 88 canbe seen. The refractor assembly 80 can be incrementally adjusted bothvertically in the direction of arrow 112 and horizontally in thedirection of arrow 113. This allows the assembly to be adjusted to suitretraction geometry for each particular patient.

FIGS. 14 a-e show various configurations of retractor blades 130, 131,132, 133 and 134 which can be detachable removed from the retractorassembly 80. Blade 130 has a distal end 135 which terminates in anengaging point 136 and a proximal end 137 which connects to retractionassembly 80. Similarly blades 131, 132, 133 and 134 have respective ends138, 139, 140 and 141 which engage refractor assembly 80. It will beappreciated by persons skilled in the art that there are many retractorblade configurations which can be connected to the retractor assembly 80(See FIGS. 10 and 11). In each case the selection of retractor bladesize, length, curvature or geometry can be determined by the surgicalrequirements and /or patient anatomy.

FIG. 15 shows a schematic arrangement of a retractor assembly 150 inuse. Assembly 150 comprises a first supporting member 151 having a firstend 152 and second end 153. First end 152 engages an adjusting assembly154 which comprises a connecting assembly 155. Second end 153 engages aconnector 156 which retains a retractor blade 157. Depending fromconnecting assembly 155 is retaining arm 158 which retains a heightadjustable clamping member 159. Clamping member 159 is capable ofmovement relative to retaining arm 158 and comprises a first end 160terminating in a bearing face 161 which opposes the patient body andretractor blade 157 and a second end 162 which includes an actuatingmember 163 which enables selective adjustment of the position ofclamping member 159 relative to retaining arm 157. Connecting assembly155 includes a runner 164 which travels along support member 151.Retaining arm 158 engages runner 164 via end 165. Runner 164 furthercomprises an actuator 166 which engages support member 151 andcontributes to retention of runner 164 in a position selected by a userof the retractor assembly 150. Actuator 166 is pivotally attached torunner 164 by abutments 167 and 168. Locking screw 169 retains runner164 against first support member 151 and allows fine adjustment of therunner 164 relative to supporting member 151. This allows a user toselectively adjust a distance d between bearing face 161 and retractorblade 157. The refractor blade 157 resists a force applied to the skin170 of a patient. Bearing face 161 applies pressure to bearing member171. Bearing member 171 can be a plate or softer pliable or elasticmaterial which can gently transmit compression to the skin.

Bearing plate 161 or bearing member 171 could be considerably larger andvarious shapes to spread clamping force across larger body surface areato accommodate particular anatomical requirements e.g. in cervicalsurgery.

FIG. 16 shows a cross sectional elevation of a clamping retractorassembly 180 showing a tooth 210 of blade 187 engaging an annulus 198.Assembly 180 comprises a supporting member 181 having a first end 182and second end 183. First end 182 engages an adjusting assembly 184which comprises a connecting assembly 185. Second end 183 engages aconnector 186 which retains a refractor blade 187. Depending fromconnecting assembly 185 is retaining arm 188 which retains a heightadjustable clamping member 189. Clamping member 189 is capable ofmovement relative to retaining arm 188 and comprises a first end 200terminating in a bearing face 201 which opposes the patient body andretractor blade 187 and a second end 202 which includes an actuatingmember 203 which enables selective adjustment of the position ofclamping member 189 relative to retaining arm 187. Connecting assembly185 includes a runner 204 which travels along support member 181.Retaining arm 188 engages runner 204. Runner 204 further comprises anactuator 206 which engages support member 181 and contributes toretention of runner 204 in a position selected by a user of theretractor assembly 180. Locking screw 207 retains runner 204 againstfirst support member 181 and allows adjustment of the runner 204relative to supporting member 181. The retractor blade 187 resists aforce applied to the skin 208 of a patient. Bearing face 201 appliespressure to bearing member 209. Bearing member 209 can be a plate orsofter pliable or elastic material which can gently transmit compressionto the skin 208. Retracting blade 187 is curved towards annulus 198.This geometry increases retraction efficiency and allows the blade 187and clamp 189 to co operate to balance forces generated for retractionstabilising the retraction assembly G clamp. Tooth 210 of blade 187 fitsinto a cut disc space. As the G Clamp blade 187 retracts, the tooth 210inside the disc space prevents the blade from lateral motions (i.e.relative to a longitudinal axis of the disc) and prevents it fromlifting up. Since the blade is in the cut disc space the cut discannulus limits and prevents the blade from going too far backwards andover compressing the tissues. The surgeon is thus able to define how farthe retractor will move backwards by cutting the annulus posteriorly tothe desired posterior limit. The ability to limit and set the amount ofposterior motion by using the cut annulus 198 (which is a toughstructure), is a useful advantage for the surgeon and is enabled by theG clamp. Retraction can be wound back or wound up using the ratchetmechanism described earlier but using the cut annulus 198 allowsprevention of over compression of tissues. The reverse angled distaltooth 210 included in blade 187 allows improved surgical method forrefraction. Blade 187 with its reverse angled distal tooth 210 requiresa cut to be made in the annulus 198, the posterior limit of which isdetermined by the surgeon. The distal end of the tooth 210 is engagedinto the disc either directly into the cut annulus 198 or immediatelyunder the cut annulus as shown in FIG. 15. In use after retracting theblade 157 the posterior limit of blade retraction is limited by theproximal section of tooth 188, engaging posterior limit of the cut inthe annulus. The section of distal tooth lying horizontally beneath theposterior limit of the cut prevents the blade by lifting up or laterallyout of the disc space. This provides increased stability for theretractor blade 187. One purpose and advantage of the apparatuses asillustrated in a surgical context is to avoid excessive retraction ofthe psoas muscle and potential injury of the lumbar nerves containedwithin this muscle. This method of limiting the amount of retraction bycutting the patient's vertebral disc is enabled in this case byinserting a tooth 210 of blade 187 to limit lift retractor blade out. isnovel, as is its application using the assembly shown in FIG. 15. Thismethod and instrumentation has particular value in an oblique oranterior to psoas approach to the spine. The assembly shown in use inFIGS. 15,16, and 17(below) is particularly useful in an anterior topsoas approach to the lumbar spine. In this approach retraction of psoasby the assembly shown in FIG. 15, allows disc access by offsetinstruments to allow an orthogonal approach to the disc space(particularly L45 and L5/s1 disc spaces) which is desirable. Bony orsoft tissue anatomy would otherwise prevent being truly orthogonal tothe disc spaces essential for maximum safety in this surgery. Refer toFIGS. 18 and 19 below. With conventional systems the bony anatomy of thepelvis would prevent use of straight instruments being orthogonal tospine.

FIG. 17 shows a surgical incision 190 in the skin 191 of a patient withretractor blade 192 showing blade 192 in use. Blade 192 has a distal endtooth 193 that curves backwards. (see also the blade 157 in FIG. 15).Blade 192 is retained by support member 194 which has thecharacteristics of the refractor assembly 150 as described in FIG. 15.Blade 192 retains tissues 195 and gains its purchase from a bearingplate (see FIG. 16).

FIG. 18 shows a surgical incision in the skin 230 of a patient with a GClamp 220 according to the invention and used in conjunction withanother retractor 221 and offset tool 222. Blade 223 has a distal endreverse tooth 224 that curves backwards. Blade 223 is retained bysupport member 225 which has similar operation and characteristics ofthe retractor assembly 150 as described in FIG. 15 so further detaileddescription of tis operation is not required. Blade 223 retains tissues226 and gains its purchase from a bearing plate 227 (see FIG. 19)associated with clamping assembly 228. In this approach retraction ofpsoas by the assembly shown allows disc access by offset instrument 222to allow an orthogonal approach to the disc space 229 (particularly L45and L5/s1 disc spaces) which is desirable. Bony or soft tissue anatomywould otherwise prevent being truly orthogonal to the disc spacesessential for maximum safety in this surgery.

FIG. 19 shows a cross sectional elevation of the arrangement of G clamp220 of figure showing a reverse tooth 224 of retractor blade 223engaging an annulus 250. Assembly 220 comprises a supporting member 231having a first end 232 and second end 233. First end 232 engages anadjusting assembly 234 which comprises a connecting assembly 235. Secondend 233 engages a connector 236 which retains retractor blade 223.Retaining arm 238 retains a height adjustable clamping member 239 whichis capable of movement relative to retaining arm 238. Bearing face 240opposes patient body 230 and retractor blade 223 and includes anactuating member 241 which enables selective adjustment of the positionof clamping assembly 228 relative to retaining arm 238. A runner 243which travels along support member 231 comprises an actuator 244 whichengages support member 231 and contributes to retention of runner 243 ina position selected by a user of the retractor assembly 220. Tooth 224of blade 223 fits into a cut disc space. As the G Clamp blade 223retracts, the tooth 224 inside the disc space prevents the blade fromlateral motions (i.e. relative to a longitudinal axis of the disc) andprevents it from lifting up. Since the blade is in the cut disc spacethe cut disc annulus limits and prevents the blade from going too farbackwards and over compressing the tissues. The surgeon is thus able todefine how far the retractor will move backwards by cutting the annulus250 posteriorly to the desired posterior limit. Retraction can be woundback or wound up using the ratchet mechanism described earlier but usingthe cut annulus allows prevention of over compression of tissues.

Other Applications for Percutaneous Retractor Handle Technology

Another spinal operation, where retraction of muscles is difficult isfor lumbar pedicle screw insertion. This is difficult because of theforce required to get the correct line of entry for screw insertiontools from a conventional midline approach. Strong retraction isrequired and this has led to very strong devices which may easily injuremuscles. Attempts to improve efficiency by using metal retractors whichlever off the bone may injure the bone, facet joints or fracture thetransverse process. A percutaneous handle would help stabilize and avoidsuch a need.

Another circumstance where retractor stability is an issue is when usingtubular retractors inserted as a series of increasing size tubes. Theseoften require table fixation to stabilize as direction of entry may bedisplace by tissue forces. Table mounting is often required tostabilize. A percutaneous handle would help stabilize and avoid such aneed.

A further circumstance where retractor stability is an issue is whenusing multi bladed retractors that are inserted as part of an assemblyand then inserted within the wound. Opening retractor may move retractorfrom desired position and often requires the addition of a table mountedarm. An alternate method of stabilizing will be to add percutaneoushandle to a. Handle is stable in body wall but this stability can befurther increased by addition of counterforce plate which may compressbody wall against sides of retractor. Percutaneous handles may also beemployed in other forms of surgery e.g. gynaecological or pelvic surgerywhere approach is via body cavity but application of retractor forcewould be helpful.

It will be recognised by persons skilled in the art that numerousvariations and modifications may be made to the invention broadlydescribed herein without departing from the overall spirit and scope ofthe invention.

1. An assembly for retracting soft tissue in a surgical incision, theassembly comprising; a supporting member having first and second ends; aretractor blade having a first distal end and a second proximal endretained at the first end of the support member; a retaining arm whichco operates with the support member and receives and supports a clampingassembly; an adjusting assembly which engages the support member andallows the clamping assembly to advance and retract relative to theretractor blade.
 2. An assembly according to claim 1 wherein theclamping assembly advances and retracts over a distance relative to thedistal end of the retractor blade and depending upon the retractionforce required.
 3. An assembly according to claim 2 wherein the clampingassembly is adjustable relative to the retaining arm.
 4. An assemblyaccording to claim 3 wherein the clamping assembly includes a clampingmember which is adjustable vertically relative to the retaining arm. 5.An assembly according to claim 4 wherein the adjusting assembly includesa runner retained on the support member.
 6. An assembly according toclaim 5 wherein the runner receives and supports a first end of theretaining arm.
 7. An assembly according to claim 6 wherein the runner isadjustable incrementally along the length of the support member.
 8. Anassembly according to claim 7 wherein the runner includes a lockingassembly which allows locking of the runner at a selected position alongthe support member.
 9. An assembly according to claim 8 wherein theclamping member is capable of advancing and retracting relative to theretractor blade responsive to travel of the runner along the supportarm.
 10. An assembly according to claim 9 wherein the runner isincrementally adjustable along the length of the support member via aratchet assembly.
 11. An assembly according to claim 9 wherein therunner is incrementally adjustable along the length of the supportmember via spaced apart holes in the support member.
 12. An assemblyaccording to claim 11 wherein the retaining arm has first and secondparts and is capable of telescopic length adjustment.
 13. An assemblyaccording to claim 12 wherein the length adjustment of the retaining armis effected by relative movement between the first and second parts. 14.An assembly according to claim 13 wherein one part is selectivelysecured to the second part by a retaining pin which engages openings oneach said first and second parts.
 15. An assembly according to claim 14wherein the clamping assembly is retained on one of said first andsecond parts of the retaining arm and is capable of transverse movementrelative to the retaining arm.
 16. An assembly according to claim 15wherein a clamping member of the clamping assembly includes a pressureplate.
 17. An assembly according to claim 16 wherein the retractor bladeis integral with the support member.
 18. An assembly according to claim17 wherein the retaining arm engages the support member via a slot inthe retaining arm.
 19. An assembly according to claim 10 wherein theclamping assembly includes a boss which allows selective verticaladjustment of the clamping member along the retaining arm.
 20. Anassembly according to claim 19 wherein the boss is spring biased to aposition which locks the clamping member against the retaining arm. 21.An assembly according to claim 20 wherein the boss includes a manuallyoperable locking screw which locks the runner to the support member. 22.An assembly according to claim
 21. wherein the boss includes a pin whichselectively engages spaced apart recesses in said retaining arm.
 23. Anassembly according to claim 22 wherein the retractor blade is releasablefrom the first end of the support member.
 24. An assembly according toclaim 23 wherein the support member includes along at least one face anarray of teeth which co operate with the ratchet assembly.
 25. Anassembly according to claim 24 wherein the location of the runner alongthe support member is incrementally adjustable by co operation betweenthe teeth and ratchet assembly.
 26. An assembly according to claim 25wherein the retractor blade is curved in the direction of the clampingmember.
 27. An assembly according to claim 26 wherein the curvature ofthe retractor blade places the distal end of the retractor blade closerto the retaining arm than the second end of said blade.
 28. An assemblyaccording to claim 27 wherein the blade is elastically deformable. 29.An assembly according to claim 28 wherein the clamping member furthercomprises a bearing member which directly engages the body of a patientwhen the retraction assembly is in use thereby allowing the retractor toretain soft tissue.
 30. An assembly according to claim 29 wherein aretraction force is increased or decreased by selective adjustment ofthe position of the runner.
 31. An assembly according to claim 29wherein a retraction force is increased or decreased by selectiveadjustment of the position of the clamping member.
 32. An assemblyaccording to claim 31 wherein the bearing member provides an opposingforce against retraction of soft tissue to maintain the desiredretraction force through the retractor blade.
 33. An assembly accordingto claim 32 wherein the retraction assembly is adjustable to allow theclamping assembly to travel in the direction of the support member andin a direction parallel to the support member.
 34. A method forretracting soft tissue in a surgical would during spinal surgery usingan assembly comprising; a retractor blade having a first distal end anda second end which engages a support member; and an adjustable stopwhich engages a pressure plate which co operates with the retractorblade during refraction by applying pressure to the body of a patient,the method comprising the steps of ; taking the retractor blade andattaching it to the support member; inserting the retractor blade into asurgical incision; adjusting a clamping assembly which co operates witha retaining member to exert a retraction force on the retractor blade;allowing a bearing member to engage a skin surface of a patient;manipulating the support member to induce retraction of the soft tissueagainst a bearing force applied by the bearing member opposite to thedirection of retraction.
 35. A retractor blade for use with a retractingassembly for retracting soft tissue in a surgical incision, the assemblycomprising; a supporting member for supporting the retractor blade; anadjusting assembly which allows the assembly to advance and retractrelative to induce retraction force in the retractor blade; theretractor blade having a proximal end which engages the retractingassembly and a distal end which is characterised in having a formationwhich is capable of engaging an anatomical structure to resist pull outof the blade.
 36. A retractor blade according to claim 35 wherein theformation at the distal end is a sharp point.
 37. A retractor bladeaccording to claim 36 wherein the formation is disposed in a plane at anangle to a plane at the distal end of the blade.
 38. A retractor bladeaccording to claim 37 wherein the formation points in the generaldirection of a force opposing retraction.